]>
Commit | Line | Data |
---|---|---|
d5efd131 MF |
1 | /* Optimized version of the standard strchr() function. |
2 | This file is part of the GNU C Library. | |
04277e02 | 3 | Copyright (C) 2000-2019 Free Software Foundation, Inc. |
d5efd131 MF |
4 | Contributed by Dan Pop <Dan.Pop@cern.ch>. |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Lesser General Public | |
8 | License as published by the Free Software Foundation; either | |
9 | version 2.1 of the License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Lesser General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public | |
75efb018 | 17 | License along with the GNU C Library; if not, see |
5a82c748 | 18 | <https://www.gnu.org/licenses/>. */ |
d5efd131 MF |
19 | |
20 | /* Return: the address of the first occurence of chr in str or NULL | |
21 | ||
22 | Inputs: | |
23 | in0: str | |
24 | in1: chr | |
25 | ||
26 | A modified version of memchr.S, the search ends when the character is | |
27 | found or the terminating null character is encountered. | |
28 | ||
29 | This implementation assumes little endian mode. For big endian mode, | |
30 | the instruction czx1.r should be replaced by czx1.l. */ | |
31 | ||
32 | #include <sysdep.h> | |
33 | #undef ret | |
34 | ||
35 | #define saved_lc r18 | |
36 | #define poschr r19 | |
37 | #define pos0 r20 | |
38 | #define val1 r21 | |
39 | #define val2 r22 | |
40 | #define tmp r24 | |
41 | #define chrx8 r25 | |
42 | #define loopcnt r30 | |
43 | ||
44 | #define str in0 | |
45 | #define chr in1 | |
46 | ||
47 | ENTRY(strchr) | |
48 | .prologue | |
49 | alloc r2 = ar.pfs, 2, 0, 0, 0 | |
50 | .save ar.lc, saved_lc | |
51 | mov saved_lc = ar.lc // save the loop counter | |
52 | .body | |
0347518d | 53 | mov ret0 = str |
d5efd131 MF |
54 | and tmp = 7, str // tmp = str % 8 |
55 | mux1 chrx8 = chr, @brcst | |
56 | extr.u chr = chr, 0, 8 // retain only the last byte | |
57 | cmp.ne p8, p0 = r0, r0 // clear p8 | |
58 | ;; | |
59 | sub loopcnt = 8, tmp // loopcnt = 8 - tmp | |
60 | cmp.eq p6, p0 = tmp, r0 | |
61 | (p6) br.cond.sptk .str_aligned;; | |
62 | adds loopcnt = -1, loopcnt;; | |
63 | mov ar.lc = loopcnt | |
64 | .l1: | |
65 | ld1 val2 = [ret0], 1 | |
66 | ;; | |
67 | cmp.eq p6, p0 = val2, chr | |
68 | cmp.eq p7, p0 = val2, r0 | |
69 | (p6) br.cond.spnt .restore_and_exit | |
70 | (p7) br.cond.spnt .notfound | |
71 | br.cloop.sptk .l1 | |
72 | .str_aligned: | |
73 | ld8 val1 = [ret0], 8;; | |
74 | nop.b 0 | |
75 | nop.b 0 | |
0347518d | 76 | .l2: |
d5efd131 | 77 | ld8.s val2 = [ret0], 8 // don't bomb out here |
0347518d | 78 | czx1.r pos0 = val1 |
d5efd131 MF |
79 | xor tmp = val1, chrx8 // if val1 contains chr, tmp will |
80 | ;; // contain a zero in its position | |
81 | czx1.r poschr = tmp | |
82 | cmp.ne p6, p0 = 8, pos0 | |
83 | ;; | |
84 | cmp.ne p7, p0 = 8, poschr | |
85 | (p7) br.cond.spnt .foundit | |
86 | (p6) br.cond.spnt .notfound | |
87 | chk.s val2, .recovery | |
88 | .back: | |
0347518d | 89 | mov val1 = val2 |
d5efd131 MF |
90 | br.cond.dptk .l2 |
91 | .foundit: | |
92 | (p6) cmp.lt p8, p0 = pos0, poschr // we found chr and null in the word | |
93 | (p8) br.cond.spnt .notfound // null was found before chr | |
94 | add ret0 = ret0, poschr ;; | |
95 | adds ret0 = -15, ret0 ;; // should be -16, but we decrement | |
96 | .restore_and_exit: // ret0 in the next instruction | |
97 | adds ret0 = -1, ret0 // ret0 was pointing 1 char too far | |
98 | mov ar.lc = saved_lc // restore the loop counter | |
99 | br.ret.sptk.many b0 | |
100 | .notfound: | |
101 | mov ret0 = r0 // return NULL if null was found | |
102 | mov ar.lc = saved_lc | |
103 | br.ret.sptk.many b0 | |
104 | .recovery: | |
105 | adds ret0 = -8, ret0;; | |
106 | ld8 val2 = [ret0], 8 // bomb out here | |
107 | br.cond.sptk .back | |
108 | END(strchr) | |
109 | ||
110 | weak_alias (strchr, index) | |
111 | libc_hidden_builtin_def (strchr) |